[13] | 1 | package de.ugoe.cs.eventbench.models;
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[12] | 2 |
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[93] | 3 | import java.security.InvalidParameterException;
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| 4 | import java.util.ArrayList;
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| 5 | import java.util.LinkedHashSet;
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[12] | 6 | import java.util.LinkedList;
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| 7 | import java.util.List;
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| 8 | import java.util.Random;
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[80] | 9 | import java.util.Set;
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[12] | 10 |
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| 11 | import de.ugoe.cs.eventbench.data.Event;
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[23] | 12 | import de.ugoe.cs.eventbench.models.Trie.Edge;
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| 13 | import de.ugoe.cs.eventbench.models.Trie.TrieVertex;
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| 14 | import edu.uci.ics.jung.graph.Tree;
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[12] | 15 |
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[17] | 16 | public abstract class TrieBasedModel implements IStochasticProcess {
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[12] | 17 |
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[86] | 18 | /**
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| 19 | * Id for object serialization.
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| 20 | */
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| 21 | private static final long serialVersionUID = 1L;
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| 22 |
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[16] | 23 | protected int trieOrder;
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[12] | 24 |
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| 25 | protected Trie<Event<?>> trie;
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| 26 | protected final Random r;
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| 27 |
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| 28 |
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[16] | 29 | public TrieBasedModel(int markovOrder, Random r) {
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[12] | 30 | super();
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[16] | 31 | this.trieOrder = markovOrder+1;
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[12] | 32 | this.r = r;
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| 33 | }
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| 34 |
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| 35 | public void train(List<List<Event<?>>> sequences) {
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| 36 | trie = new Trie<Event<?>>();
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| 37 |
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| 38 | for(List<Event<?>> sequence : sequences) {
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| 39 | List<Event<?>> currentSequence = new LinkedList<Event<?>>(sequence); // defensive copy
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| 40 | currentSequence.add(0, Event.STARTEVENT);
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| 41 | currentSequence.add(Event.ENDEVENT);
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| 42 |
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[16] | 43 | trie.train(currentSequence, trieOrder);
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[12] | 44 | }
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| 45 | }
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| 46 |
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[17] | 47 | /* (non-Javadoc)
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| 48 | * @see de.ugoe.cs.eventbench.models.IStochasticProcess#randomSequence()
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| 49 | */
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| 50 | @Override
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[12] | 51 | public List<? extends Event<?>> randomSequence() {
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| 52 | List<Event<?>> sequence = new LinkedList<Event<?>>();
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| 53 |
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[16] | 54 | IncompleteMemory<Event<?>> context = new IncompleteMemory<Event<?>>(trieOrder-1);
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[12] | 55 | context.add(Event.STARTEVENT);
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| 56 |
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| 57 | Event<?> currentState = Event.STARTEVENT;
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| 58 |
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| 59 | boolean endFound = false;
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| 60 |
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| 61 | while(!endFound) {
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| 62 | double randVal = r.nextDouble();
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| 63 | double probSum = 0.0;
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[16] | 64 | List<Event<?>> currentContext = context.getLast(trieOrder);
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[12] | 65 | for( Event<?> symbol : trie.getKnownSymbols() ) {
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| 66 | probSum += getProbability(currentContext, symbol);
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| 67 | if( probSum>=randVal ) {
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| 68 | endFound = (symbol==Event.ENDEVENT);
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| 69 | if( !(symbol==Event.STARTEVENT || symbol==Event.ENDEVENT) ) {
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| 70 | // only add the symbol the sequence if it is not START or END
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| 71 | context.add(symbol);
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| 72 | currentState = symbol;
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| 73 | sequence.add(currentState);
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| 74 | }
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| 75 | break;
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| 76 | }
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| 77 | }
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| 78 | }
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| 79 | return sequence;
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| 80 | }
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[23] | 81 |
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[30] | 82 | public String getTrieDotRepresentation() {
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| 83 | return trie.getDotRepresentation();
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| 84 | }
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| 85 |
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[23] | 86 | public Tree<TrieVertex, Edge> getTrieGraph() {
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| 87 | return trie.getGraph();
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| 88 | }
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[12] | 89 |
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| 90 | @Override
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| 91 | public String toString() {
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| 92 | return trie.toString();
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| 93 | }
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[66] | 94 |
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| 95 | public int getNumStates() {
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| 96 | return trie.getNumSymbols();
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| 97 | }
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[70] | 98 |
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| 99 | public String[] getStateStrings() {
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| 100 | String[] stateStrings = new String[getNumStates()];
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| 101 | int i=0;
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| 102 | for( Event<?> symbol : trie.getKnownSymbols() ) {
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| 103 | stateStrings[i] = symbol.toString();
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| 104 | i++;
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| 105 | }
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| 106 | return stateStrings;
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| 107 | }
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[80] | 108 |
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[93] | 109 | public Set<? extends Event<?>> getEvents() {
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[80] | 110 | return trie.getKnownSymbols();
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| 111 | }
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[93] | 112 |
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| 113 | public Set<List<? extends Event<?>>> generateSequences(int length) {
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[94] | 114 | return generateSequences(length, false);
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| 115 | /*Set<List<? extends Event<?>>> sequenceSet = new LinkedHashSet<List<? extends Event<?>>>();;
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[93] | 116 | if( length<1 ) {
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| 117 | throw new InvalidParameterException("Length of generated subsequences must be at least 1.");
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| 118 | }
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| 119 | if( length==1 ) {
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| 120 | for( Event<?> event : getEvents() ) {
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| 121 | List<Event<?>> subSeq = new LinkedList<Event<?>>();
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| 122 | subSeq.add(event);
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| 123 | sequenceSet.add(subSeq);
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| 124 | }
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| 125 | return sequenceSet;
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| 126 | }
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| 127 | Set<? extends Event<?>> events = getEvents();
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| 128 | Set<List<? extends Event<?>>> seqsShorter = generateSequences(length-1);
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| 129 | for( Event<?> event : events ) {
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| 130 | for( List<? extends Event<?>> seqShorter : seqsShorter ) {
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| 131 | Event<?> lastEvent = event;
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| 132 | if( getProbability(seqShorter, lastEvent)>0.0 ) {
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| 133 | List<Event<?>> subSeq = new ArrayList<Event<?>>(seqShorter);
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| 134 | subSeq.add(lastEvent);
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| 135 | sequenceSet.add(subSeq);
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| 136 | }
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| 137 | }
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| 138 | }
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| 139 | return sequenceSet;
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[94] | 140 | */
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[93] | 141 | }
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[94] | 142 |
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| 143 | // if startValid, all sequences will start in Event.STARTEVENT
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| 144 | public Set<List<? extends Event<?>>> generateSequences(int length, boolean fromStart) {
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| 145 | Set<List<? extends Event<?>>> sequenceSet = new LinkedHashSet<List<? extends Event<?>>>();;
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| 146 | if( length<1 ) {
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| 147 | throw new InvalidParameterException("Length of generated subsequences must be at least 1.");
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| 148 | }
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| 149 | if( length==1 ) {
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| 150 | if( fromStart ) {
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| 151 | List<Event<?>> subSeq = new LinkedList<Event<?>>();
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| 152 | subSeq.add(Event.STARTEVENT);
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[95] | 153 | sequenceSet.add(subSeq);
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[94] | 154 | } else {
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| 155 | for( Event<?> event : getEvents() ) {
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| 156 | List<Event<?>> subSeq = new LinkedList<Event<?>>();
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| 157 | subSeq.add(event);
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| 158 | sequenceSet.add(subSeq);
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| 159 | }
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| 160 | }
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| 161 | return sequenceSet;
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| 162 | }
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| 163 | Set<? extends Event<?>> events = getEvents();
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[95] | 164 | Set<List<? extends Event<?>>> seqsShorter = generateSequences(length-1, fromStart);
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[94] | 165 | for( Event<?> event : events ) {
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| 166 | for( List<? extends Event<?>> seqShorter : seqsShorter ) {
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| 167 | Event<?> lastEvent = event;
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| 168 | if( getProbability(seqShorter, lastEvent)>0.0 ) {
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| 169 | List<Event<?>> subSeq = new ArrayList<Event<?>>(seqShorter);
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| 170 | subSeq.add(lastEvent);
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| 171 | sequenceSet.add(subSeq);
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| 172 | }
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| 173 | }
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| 174 | }
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| 175 | return sequenceSet;
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| 176 | }
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| 177 |
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| 178 | // sequences from start to end
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| 179 | public Set<List<? extends Event<?>>> generateValidSequences(int length) {
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| 180 | // check for min-length implicitly done by generateSequences
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[95] | 181 | Set<List<? extends Event<?>>> allSequences = generateSequences(length, true);
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| 182 | Set<List<? extends Event<?>>> validSequences = new LinkedHashSet<List<? extends Event<?>>>();
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| 183 | for( List<? extends Event<?>> sequence : allSequences ) {
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| 184 | if( sequence.size()==length && Event.ENDEVENT.equals(sequence.get(sequence.size()-1)) ) {
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| 185 | validSequences.add(sequence);
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[94] | 186 | }
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| 187 | }
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| 188 | return validSequences;
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| 189 | }
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[12] | 190 |
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| 191 | } |
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